Chalcone-1-Deoxynojirimycin Heterozygote Reduced the Blood Glucose Concentration and Alleviated the Adverse Symptoms and Intestinal Flora Disorder of Diabetes Mellitus Rats.

Chalcone-1-deoxynojirimycin heterozygote (DC-5), a novel compound which was designed and synthesized in our laboratory for diabetes treatment, showed an extremely strong in vitro inhibitory activity on α-glucosidase in our previous studies. In the current research, its potential in vivo anti-diabetic effects were further investigated by integration detection and the analysis of blood glucose concentration, blood biochemical parameters, tissue section and gut microbiota of the diabetic rats. The results indicated that oral administration of DC-5 significantly reduced the fasting blood glucose and postprandial blood glucose, both in diabetic and normal rats; meanwhile, it alleviated the adverse symptoms of elevated blood lipid level and lipid metabolism disorder in diabetic rats. Furthermore, DC-5 effectively decreased the organ coefficient and alleviated the pathological changes of the liver, kidney and small intestine of the diabetic rats at the same time. Moreover, the results of 16S rDNA gene sequencing analysis suggested that DC-5 significantly increased the ratio of Firmicutes to Bacteroidetes and improved the disorder of gut microbiota in diabetic rats. In conclusion, DC-5 displayed a good therapeutic effect on the diabetic rats, and therefore had a good application prospect in hypoglycemic drugs and foods.

The anti-obesity and gut microbiota modulating effects of taxifolin in C57BL/6J mice fed with a high-fat diet.

BACKGROUND: Taxifolin is a natural dihydroflavonol found in many plants and health products. In the present study, its anti-obesity and gut microbiota modulating effects were studied. C57BL/6J mice were fed with a high-fat diet (HFD) supplemented with taxifolin (0, 0.5 and 1 mg mL-1 , respectively) in drinking water for 15 weeks. RESULTS: Taxifolin supplementation showed no influence on food and water intake. However, it decreased body weight gain, inhibited fat accumulation, and decreased total cholesterol and triacylglycerol level in mice liver. Taxifolin enhanced superoxide dismutase (SOD) activity in mice liver, which in turn protected the liver from lipid peroxidation damage. It also improved insulin resistance in obese mice. Metagenomic analysis of bacterial 16S rRNA demonstrated that HFD decreased gut microbiota diversity and caused dysbiosis. However, taxifolin improved the gut microbiota diversity and decreased the Firmicutes/Bacteroidetes ratio. In particular, it inhibited Proteobacteria from blooming, this being a signature of dysbiosis in gut microbiota. CONCLUSION: Taxifolin ameliorated the symptoms of obesity, hepatic steatosis, lipid peroxidation, insulin resistance, and gut microbiota dysbiosis in HFD fed C57BL/6J mice. © 2021 Society of Chemical Industry.

Physicochemical properties of dihydromyricetin and the effects of ascorbic acid on its stability and bioavailability.

BACKGROUND: Dihydromyricetin (DMY) is a natural dihydroflavonol with many bioactive effects. However, the physicochemical properties of DMY related to its bioavailability, especially its stability, are unclear. RESULTS: The effects of pH, temperature, metal ions and ascorbic acid (AA) on the stability of DMY were studied using high-performance liquid chromatography (HPLC). The bioavailability of DMY in the presence and absence of AA was compared. Dihydromyricetin was unstable in weak alkaline solutions, and the degradation was significantly accelerated in the presence of Cu2+ and Fe3+ . The degradation process followed the first-order kinetic model. The degradation rate constant (k) increased with increasing pH and temperature. The remaining DMY was only 49% of its initial concnentration after 4 h in simulated intestinal fluid (SIF) at 37 °C. However, by supplementing with AA, the degradation of DMY was rarely occured within 6 h. The solubility of DMY at pH 3-5 was about 750 µg mL-1 , slightly increasing to 853 µg mL-1 at pH 6. Pharmacokinetic studies showed that the bioavailability of DMY increased from 0.122% to 0.341% by supplementing with AA (10% of DMY). CONCLUSION: The degradation of DMY is one reason for its poor bioavailability. The presence of AA could significantly improve the stability of DMY, and further improve its bioavailability in rats. © 2020 Society of Chemical Industry.

Synthesis, in vitro inhibitory activity, kinetic study and molecular docking of novel N-alkyl-deoxynojirimycin derivatives as potential α-glucosidase inhibitors.

A series of novel N-alkyl-1-deoxynojirimycin derivatives 25 ∼ 44 were synthesised and evaluated for their in vitro α-glucosidase inhibitory activity to develop α-glucosidase inhibitors with high activity. All twenty compounds exhibited α-glucosidase inhibitory activity with IC50 values ranging from 30.0 ± 0.6 µM to 2000 µM as compared to standard acarbose (IC50 = 822.0 ± 1.5 µM). The most active compound 43 was ∼27-fold more active than acarbose. Kinetic study revealed that compounds 43, 40, and 34 were all competitive inhibitors on α-glucosidase with Ki of 10 µM, 52 µM, and 150 µM, respectively. Molecular docking demonstrated that the high active inhibitors interacted with α-glucosidase by four types of interactions, including hydrogen bonds, π-π stacking interactions, hydrophobic interactions, and electrostatic interaction. Among all the interactions, the π-π stacking interaction and hydrogen bond played a significant role in a various range of activities of the compounds.

A Comparison of Solubility, Stability, and Bioavailability between Astilbin and Neoastilbin Isolated from Smilax glabra Rhizoma.

Astilbin and neoastilbin are two flavonoid stereoisomers. In the present study, their solubility, stability, and bioavailability were compared in a rat. The results revealed that the water solubility of astilbin and neoastilbin was 132.72 µg/mL and 217.16 µg/mL, respectively. The oil-water distribution coefficient (log P) of astilbin and neoastilbin in simulated gastric fluid (SGF) was 1.57 and 1.39, and in simulated intestinal fluid (SIF) was 1.09 and 0.98, respectively. In SIF, about 78.6% astilbin remained after 4 h of incubation at 37 °C, while this value was 88.3% for neoastilbin. Most of the degraded astilbin and neoastilbin were isomerized into their cis-trans-isomer, namely neoisoastilbin and isoastilbin, respectively, and the decomposed parts were rare. For bioavailability comparison in a rat, an HPLC method for trace amounts of astilbin and neoastilbin determination in plasma was developed, and the pretreatment of plasma was optimized. A pharmacokinetic study showed that the absolute bioavailability of astilbin and neoastilbin in a rat showed no significant difference with values of 0.30% and 0.28%, respectively.

Investigating the induction of polyphenol biosynthesis in the cultured Cycolocarya paliurus cells and the stimulatory mechanism of co-induction with 5-aminolevulinic acid and salicylic acid.

Background: Plant cell culture technology is a potential way to produce polyphenols, however, this way is still trapped in the dilemma of low content and yield. Elicitation is regarded as one of the most effective ways to improve the output of the secondary metabolites, and therefore has attracted extensive attention. Methods: Five elicitors including 5-aminolevulinic acid (5-ALA), salicylic acid (SA), methyl jasmonate (MeJA), sodium nitroprusside (SNP) and Rhizopus Oryzae Elicitor (ROE) were used to improve the content and yield of polyphenols in the cultured Cyclocarya paliurus (C. paliurus) cells, and a co-induction technology of 5-ALA and SA was developed as a result. Meanwhile, the integrated analysis of transcriptome and metabolome was adopted to interpret the stimulation mechanism of co-induction with 5-ALA and SA. Results: Under the co-induction of 50 µM 5-ALA and SA, the content and yield of total polyphenols of the cultured cells reached 8.0 mg/g and 147.12 mg/L, respectively. The yields of cyanidin-3-O-galactoside, procyanidin B1 and catechin reached 28.83, 4.33 and 2.88 times that of the control group, respectively. It was found that expressions of TFs such as CpERF105, CpMYB10 and CpWRKY28 increased significantly, while CpMYB44 and CpTGA2 decreased. These great changes might further make the expression of CpF3'H (flavonoid 3'-monooxygenase), CpFLS (flavonol synthase), CpLAR (leucoanthocyanidin reductase), CpANS (anthocyanidin synthase) and Cp4CL (4-coumarate coenzyme A ligase) increase while CpANR (anthocyanidin reductase) and CpF3'5'H (flavonoid 3', 5'-hydroxylase) reduce, ultimately enhancing the polyphenols accumulation Conclusion: The co-induction of 5-ALA and SA can significantly promote polyphenol biosynthesis in the cultured C. paliurus cells by regulating the expression of key transcription factors and structural genes associated with polyphenol synthesis, and thus has a promising application.

Metabolism, tissue distribution and excretion of taxifolin in rat.

The metabolism, tissue distribution and excretion of taxifolin in rat after oral administration of taxifolin encapsulated zein-caseinate Nanoparticles (TZP) were studied. The isomerization of taxifolin in rat small intestine and colon was found. Besides isomers, 16 metabolites of taxifolin were identified in rat feces, plasma and urine by UPLC-QTOF-MS. In colon, taxifolin underwent the metabolism of hydration, dehydration and ring-fission through the gut microflora. The main metabolites of taxifolin found in plasma and urine were its sulfated, glucuronidated, and/or methylated products. The dynamic variation of taxifolin and its metabolites in tissues and urine were quantified by UPLC-QqQ-MS/MS. Taxifolin and its metabolites could be quickly absorbed and distributed in the tissues, and relatively low concentrations were found in the heart and brain. The feces excretion of taxifolin was determined by HPLC. The total excretion during 24 h was 2.83 ± 0.80% to its given does, and the maximum excretion was found during 8-10 h post administration. Compared with feces, the excretion of taxifolin and its metabolites in urine was much faster, and the total excretion was 1.96 ± 0.23% during 12 h.

Dihydromyricetin Improves Cognitive Impairments in d-Galactose-Induced Aging Mice through Regulating Oxidative Stress and Inhibition of Acetylcholinesterase.

SCOPE: Alzheimer's disease (AD) is a neurodegenerative disease with phenomena of cognitive impairments. Oxidative stress and cholinergic system dysfunction are two widely studied pathogenesis of AD. Dihydromyricetin (DMY) is a natural dihydroflavonol with many bioactivities. In this study, it is aimed to investigate the effects of DMY on cognitive impairment in d-galactose (d-gal) induced aging mice. METHODS AND RESULTS: Mice are intraperitoneally injected with d-gal for 16 weeks, and DMY is supplemented in drinking water. The results show that DMY significantly improves d-gal-induced cognitive impairments in novel object recognition and Y-maze studies. H&E and TUNEL staining show that DMY could improve histopathological changes and cell apoptosis in mice brain. DMY effectively induces the activities of catalase, superoxide dismutase and glutathione peroxidase, and reduces malondialdehyde level in mice brain and liver. Furthermore, DMY reduces cholinergic injury by inhibiting the activity of Acetylcholinesterase (AChE) in mice brain. In vitro studies show that DMY is a non-competitive inhibitor of AChE with IC50 value of 161.2 µg mL-1 . CONCLUSION: DMY alleviates the cognitive impairments in d-gal-induced aging mice partly through regulating oxidative stress and inhibition of acetylcholinesterase.

Processing, digestion property and structure characterization of slowly digestible gorgon nut starch.

Slowly digestible gorgon nut starch (GN-SDS) was prepared by heating-cooling treatment (HCT), meanwhile its morphological and structural features were characterized in detail by SEM, DSC, XRD and IR detection. The optimized parameters of GN-SDS processing were as following: starch milk (20%) was heated at 100 °C for 20 min, and then cooled under 4 °C for 24 h. Under the optimized parameters, the SDS content increased from 20.49 to 61.74%. GN-SDS showed typical SDS characteristics in in vivo digestion with a low postprandial blood glucose. SEM images suggested that GN-S particles changed from uniform regular polyhedron with smooth surface to irregular gravel-like particles with coarse surface and obvious layered structure inside after HCT. The results of SEM, DSC, XRD and IR determination indicated that HCT changed the granule morphology, interior structure, gelatinization temperature and crystal type (A to B-type) of GN-S, and therefore made it hard to be digested accordingly. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s10068-021-01007-6.

Efficacy and Safety of Regorafenib Monotherapy among Patients with Previously Treated Metastatic Colorectal Cancer in a Chinese Population: A Real-World Exploratory Study.

BACKGROUND: Present study was condeucted to investigate the efficacy and safety of regorafenib for patients with previously treated metastatic colorectal cancer (mCRC) in a Chinese population and the prognostic implications of adverse reactions. METHODS: This retrospective study a total of 96 consecutive patients with mCRC who had failed standard chemotherapy regimens from June 2017 to December 2020. Patients received regorafenib at an initial dosage of 160 mg or 120 mg. The primary end point was progression-free survival (PFS), and secondary end points objective response rate (ORR), disease-control rate (DCR), overall survival (OS), safety, and associations between prognosis and adverse-reaction status. RESULTS: There were three patients with partial response, 49 with stable disease, and 44 with progressive disease. Consequently, the ORR and DCR of the 96 patients were 3.1% (95% CI 0.6%-8.9%) and 54.2% (95% CI 43.7-64.4%), respectively. Prognosis results showed that median PFS of the 96 patients was 2.5 (95% CI 1.98-3.02) months and median OS 9.8 (95% CI 7.02-12.59) months. Additionally, the most frequent adverse reactions during regorafenib treatment were hand-foot syndrome (HFS; 52.1%), hypertension (38.5%), and fatigue (33.3%). Interestingly, the relevance of prognosis to adverse-reaction status exhibited that median PFS of patients with HFS and patients without HFS was 3.3 months and 2.0 months, respectively (P=0.013). Similarly, median PFS of patients with hypertension and without hypertension was 3.6 months and 2.2 months, respectively (P=0.023). CONCLUSION: Potential clinical benefit of regorafenib monotherapy was observed for patients with mCRC who had failed standard chemotherapy regimens. Hypertension and HFS induced by regorafenib therapy could be used as valuable biomarkers to predict the prognosis of regorafenib.

In vivo and in vitro comparison of three astilbin encapsulated zein nanoparticles with different outer shells.

Three shell materials, lecithin (ZNP-L), chitosan (ZNP-CH) and sodium caseinate (ZNP-SC), were used to prepare core-shell zein nanoparticles. Astilbin was encapsulated as a model flavonoid to compare the influence of the shell materials on zein nanoparticles both in vitro and in vivo. The particle size was moderately increased by lecithin and sodium caseinate, but notably increased by chitosan. All the shell materials provided good redispersibility for the nanoparticles and significantly improved the colloidal stability. Chitosan and sodium caseinate significantly delayed and decreased the feces excretion of astilbin in rats, while lecithin exhibited a very weak effect. The results may be attributed to the difference in mucoadhesive properties between the shell materials. As a consequence, the bioavailability values of astilbin in rats were 18.2, 9.3 and 1.89 times increased through ZNP-CH, ZNP-SC and ZNP-L compared with that of free astilbin, respectively.

α-Glucosidase inhibitory effect of anthocyanins from Cinnamomum camphora fruit: Inhibition kinetics and mechanistic insights through in vitro and in silico studies.

α-Glucosidase inhibitors are widely used to suppress postprandial glycemia in the treatment of type 2 diabetes mellitus. The present study evaluated the in vitro α-glucosidase inhibitory activity of three major pigment constituents of Cinnamomum camphora fruit, namely cyanidin, cyanidin 3-rutinoside, and cyanidin-3-O-glucoside. We found that cyanidin exerted strong inhibitory activity on α-glucosidase, with IC50 of 5.293 × 10-3 mM, whereas cyanidin 3-rutinoside and cyanidin-3-O-glucoside did not show inhibitory activity on α-glucosidase. The inhibitory activity of cyanidin was stronger than that of acarbose (IC50 1.644 mM), the current most commonly used drug for postprandial glycemia. Kinetic analysis indicated that cyanidin inhibited α-glucosidase through competition, with a Ki value of 0.0183 mM. Fluorescence spectrum titration showed only one binding site between cyanidin and α-glucosidase, and the binding constant was calculated. Further, molecular docking was conducted to simulate the binding interactions between cyanidin and α-glucosidase. Cyanidin was found to interact with several residues close to the catalytic site of α-glucosidase through π-π stack interaction and hydrogen bonds. The calculated binding energy of the cyanidin and enzyme complex was -105.031 kJ/mol. Molecular simulation and calculation showed that the van der Waals force played an essential role in the binding of α-glucosidase and cyanidin.

In vitro and in vivo inhibitory activity of taxifolin on three digestive enzymes.

The inhibitory activity of taxifolin on three digestive enzymes were investigated in both vitro and vivo. Taxifolin exhibited inhibitory effect on α-glucosidase, α-amylase and pancreatic lipase with IC50 values of 0.038, 0.647 and 0.993 mg/mL, respectively. Inhibitory kinetics indicated that taxifolin was more like a competitive inhibitor of α-glucosidase and α-amylase, while it was a non-competitive inhibitor of pancreatic lipase. The binding of taxifolin caused the quenching of intrinsic fluorescence intensity of enzymes, and the binding constant (lgKa) and the number of binding site (n) were further calculated through fluorescence titration. The values of lgKa were in the range of 4.93-6.65, and the values of n were all close to 1. Molecular docking indicated that taxifolin could interact with α-glucosidase and α-amylase through many kinds of secondary interaction, such as hydrogen bond, π-π stack, etc. In vivo study revealed that pre-administration with taxifolin can significantly improve the postprandial hyperglycemia in rat. Furthermore, its can also decrease triglyceride absorption through the inhibition of pancreatic lipase.

Production of chlorogenic acid and its derivatives in hairy root cultures of Stevia rebaudiana.

Chlorogenic acid and its derivatives (CADs) are valuable bioactive plant secondary metabolites with many health benefits. In the present study, Stevia rebaudiana hairy root cultures were established, and the culture conditions for the production of CADs were optimized. The hairy roots were induced by coculture of S. rebaudiana leaves and Agrobacterium rhizogenes (C58C1) after infection, which were further verified by PCR detection of rolB and rolC genes. HPLC-MS and HPLC analysis showed that chlorogenic acid (3-caffeoylquinic acid, 3-CQA), 3,5-dicaffeoylquinic acid (3,5-CQA), and 4,5-dicaffeoylquinic acid (4,5-CQA) were the major CADs in the hairy roots. Eight single roots with rapid growth rate were selected. Among them, T3 had the highest yield of CADs. B5 medium supplemented with 40 g/L sucrose was more suitable for the production of CADs than others. Under optimal culture conditions, the total content of these three compounds reached 105.58 mg/g and total yield was 234.40 mg/100 mL.

Aqueous solubility and stability enhancement of astilbin through complexation with cyclodextrins.

The complexation of astilbin with α-, ß-, and γ-cyclodextrin (CD) was studied by phase solubility test and UV-vis spectral titration. Complexation with CDs gradually decreased the absorbance of astilbin at 291 nm and obviously increased its water solubility. The formation constant (K(a)) between astilbin and the three CDs was calculated. The stability of astilbin complexes increased in the order α-CD < γ-CD < ß-CD, attributed to the CDs' cavity size. Temperature studies showed that the K(a) value decreased along with the rise of temperature. The negative values of enthalpy and entropy during complexation indicated that the complexation process was enthalpy-controlled. In alkaline medium isomerization and decomposition of astilbin were found; however, the addition of CDs significantly improved its stability through complexation. The solubility of astilbin in ß-CD microcapsules prepared by the freeze-drying method was enhanced by 122.1-fold, and its dissolution profile was improved.